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Molecular Mechanisms of Sex Determination and Differentiation

性别决定和分化的分子机制

基本信息

批准号：
06044235
负责人：
NAGAHAMA Yoshitaka
金额：
$ 7.74万
依托单位：
Okazaki National Research Institutes
依托单位国家：
日本
项目类别：
Grant-in-Aid for international Scientific Research
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1996
项目状态：
已结题

项目摘要

This international collaborative research is to combine a variety of approaches and animal systems to the study of sex determination and sexual differentiation. Sex change in the endemic, Hawaiian wrasse Thalassoma duperrey provides an ideal model system to investigate mechanisms of sex determination and sexual differentiation. We first used immunocytochemical methods to detect gonadal sites of P450 cholesterol side-chain cleavage enzyme (P450scc) in the wrasse at different stages of in the sex change process. P450scc cells were predominantly in the theca layr of normal females. As females underwent sex change, P450scc localization shifted from the theca layr to the interstitium. P450scc cells appeared to increase in number midway through sex change. The gonad's ability to produce estrogens, however, is permanently lost in the earliest stages of sex change. The levels of aromatase mRNA and protein, the enzyme responsible for converting androgens to estrogens, was undetectable in testes … More and transitional gonads. In contrast, protein levels of 11beta-hydroxylase, the enzyme responsible for 11-ketotestosterone production increase towards the end of sex change process.In this collaborative research, we also examined immunocytochemically the initial differentiation and development of steroid-producing cells during gonadal sex differentiation in tilapia Oreochromis niloticus using polyclonal antibodies against four steroid-metabolizing enzymes (P450scc, 3beta-HSD,P450c17, P450arom). Immunoreaction for P450scc, 3beta-HSD,P450c17, and P450arom became evident for the first time in gonads of genetically females examined at several days before morphological sex differentiation. In contrast, positive immunostaining for all four steroidogenic enzymes was not easily identified in the testes during sex differentiation. A weak staining for P450scc, 3beta-HSD and P450c17, but not P450arom, was present in the tissue surrounding the efferent duct in testes 30 days after hatching. The number of immunoreactive cells as well as the intensity of staining ware increased in testes just before the onset of spermatogenesis. Taken together, these findings suggest that estrogens play an important role in ovarian differentiation in fish. The results of this collaborative research also suggest an important role of estrogens in temperature-dependent sexual differentiation in reptiles. Less

这项国际合作研究将联合收割机结合多种方法和动物系统来研究性别决定和性别分化。特有的夏威夷濑鱼的性别变化为研究性别决定和性别分化机制提供了理想的模式系统。本研究首先采用免疫细胞化学方法检测了隆头鱼在性别转变过程中不同阶段的性腺中P450胆固醇侧链裂解酶（P450 SCC）的表达位点。P450 SCC细胞主要分布于正常女性卵泡膜层。随着雌性发生性别改变，P450 SCC的定位从卵泡膜层转移到卵泡膜层。P450 SCC细胞出现增加的数量中途通过性别变化。然而，性腺产生雌激素的能力在性别变化的早期阶段永久丧失。芳香化酶的mRNA和蛋白质水平，这种酶负责将雄激素转化为雌激素，在睾丸中检测不到 ...更多信息和过渡性腺在本研究中，我们还利用4种类固醇代谢酶的多克隆抗体，对尼罗罗非鱼性腺性别分化过程中类固醇产生细胞的初始分化和发育进行了免疫细胞化学研究（P450SCC、3beta-HSD、P450c17、P450arom）。P450 SCC，3 β-HSD，P450 C17和P450 arom的免疫反应首次在形态性别分化前几天检查的遗传雌性性腺中变得明显。与此相反，阳性免疫染色的所有四个类固醇生成酶不容易确定在睾丸中的性别分化。P450 arom、P450 SCC、3 β-HSD和P450 c17在出壳后30天的睾丸输出管周围组织中呈弱阳性表达。在精子发生开始前，睾丸中免疫反应细胞的数量和染色强度增加。综上所述，这些发现表明雌激素在鱼类卵巢分化中起着重要作用。这项合作研究的结果还表明，雌激素在爬行动物的温度依赖性性别分化中起着重要作用。少